Anterior fixations in the area of the spinal column have been achieved with plate-shaped devices, as shown in WO94/17744, for example. Such plate-shaped devices have the great advantage of having very limited thickness (between 1.1 and 2.0 mm), and thus are only slightly invasive.
A drawback of such plate-shaped devices, however, is that the fusion zone of the affected vertebrae cannot be actively placed under pressure, which can lead to instances of pseudo-arthrosis. A further drawback is the great variety of the necessary assortment of instruments with greatly varying dimensions that are available to the surgeon. Typically, depending on the manufacturer, 12 to 23 plate types are required.
Devices with longitudinal members, as used in posterior fixation in the area of the spinal cord, have not been able to be used in clinical practice on account of their considerable thickness imposed by design limitations. However, longitudinal members have the advantage of permitting the application of active compression to the treatment site, and would require only a minimum assortment of instruments.